This invention relates generally to infectious diseases, and more specifically to methods of identifying cellular regulators essential in the pathogenesis of infectious agents.
Infectious diseases are a serious cause of death and debilitation in the United States and particularly in the non-industrialized populations of the world. In particular, Hepatitis C virus (HCV) is the major cause of non-A, non-B hepatitis, which is also a serious worldwide health problem. Approximately 1% to 2% of the world population is infected with HCV. In the United States alone, there are approximately 2.7 million infected individuals, with 150,000 acute cases occurring annually, resulting in HCV infection as the ninth leading cause of death.
Intravenous drug abuse has been indicated as one important risk factor for transmission of HCV. However, different epidemiological studies have revealed that for up to 20 to 40% of patients chronically infected with HCV, no known risk factors have been identified.
The disease associated with HCV is, in most cases, benign. Nevertheless, persistent infection can lead to liver cirrhosis and hepatocellular carcinoma. HCV disease can be manifested as acute viral hepatitis which is usually clinically mild, but may develop into a severe or fulminant hepatitis. Chronic HCV hepatitis is believed to occur more frequently than with hepatitis B virus, especially following posttransfusional acute hepatitis C disease.
Treatment of HCV infection has primarily been with alpha-interferon. In some instances liver transplantation has been performed for end-stage hepatic deficiency, but invariably the transplanted liver also becomes infected with HCV and ultimately fails.
Virally encoded gene products have been thought to be effective targets for drug development because they are unique to infected cells. However, despite the potential specificity of drugs targeting viral gene products, they have the disadvantage of rapidly becoming ineffective due to the ability of the virus to mutate and become drug resistant. This drug resistant phenomenon has been observed with both DNA and RNA virus. Moreover, similar phenomenon have been observed with other infectious agents such as paracytes which change coat proteins in response to specific targeting agents or host immune responses. In contrast, cellular genes that are essential for viral replication or expression are not rapidly mutated and therefore less susceptible to developing resistance. The availability of such cellular genes would be valuable as targets for development of new therapeutics and methods for treatment of a variety of viral and other infectious diseases.
Thus, there exists a need for the rapid and efficient identification of cellular genes involved in the propagation or pathogenesis of infectious agents. The present invention satisfies this need and provides related advantages as well.
The invention provides a substantially pure nucelic acid having a nucleotide greater than about 80% indentical to SEQ ID NO:1, or a unique fragment thereof. Also provided is a substantially pure polypeptide having an amino acid sequence greater than about 91% identical to SEQ ID NO:2, or functional fragment thereof. A substantially pure TST nucleic acid is further provided The TST nucleic acids consist of a fragment of SEQ ID NO:1 having substantially the nucleotide sequence N5-GUC-8 N5-GUA-N5 (SEQ ID NOS:3 and 4, respectively). The TST nucleic acids can be between 8-12 nucleotides at positions N5 and N8 are identical to a fragment of SEQ ID NO:1. Additionally provided is a TST nucleic acid having a sequence selected from the group consisting of 5xe2x80x2-UAGUNGUCAAAGUUAG-3xe2x80x2, 3xe2x80x2-CGCANGUCAAUAAUUA-3xe2x80x2, 5xe2x80x2-CUGANGUCUAGAUCGC-3xe2x80x2, 3xe2x80x2-AAGCNGUCUUUGGUCU-3xe2x80x2, 5xe2x80x2-CGGUNGUCCUGGCUGU-3xe2x80x2, 3xe2x80x2-CGUANGUCGCGUUUAA-3xe2x80x2, 5xe2x80x2-UUCGNGUCAGCCAAUA-3xe2x80x2, 3xe2x80x2-GCAGNGUCGAGGCUGA-3xe2x80x2, 5xe2x80x2-GCANGUCUGCCAGCU-3xe2x80x2, 3xe2x80x2-AAGUNGUCAUUAACAA-3xe2x80x2, 5xe2x80x2-AGCUNGUCAAUAAGAA-3xe2x80x2, 3xe2x80x2-UUCCNGUCUUAAGCGA-3xe2x80x2, 5xe2x80x2-AGAANGUCUUGACGAA-3xe2x80x2, 3xe2x80x2-GUCUNGUCACGUGUUA-3xe2x80x2, 5xe2x80x2-GGGANGUCCCUCGGCU3xe2x80x2, 3xe2x80x2-CGAGNGUCGUUGACAG-3xe2x80x2, 5xe2x80x2-UCCANGUCAUAUGAAU-3 xe2x80x2, 3xe2x80x2-GAUGNGUCCGCGCAAG-3xe2x80x2, 5xe2x80x2-CUGCNGUCAUGCGGCU-3xe2x80x2, (SEQ ID NOS:25-43) or a complementary sequence thereof. A method of identifying a compound that modulates the activity of a cellular regulator is further provided. The method consists of contacting a sample containing a cellular regulator and a nucleic acid element acted on by a cellular regulator with a test compound under conditions that allow replication or expression of the nucleic acid element or a gene operatively linked to the nucleic acid element, and measuring the amount of replication or expression of the nucleic acid element or gene, an increase or decrease in the amount of replicatin of expression in the presence of the test compound compared to the absence of the test compound indicates that the compound has cellular regulator modulatory activity. A method of treating a HCV infection is also provided.